I am planning on swapping parts from my damaged 1990 RS to a rolling chassis of a 1987 RS. Will my 3.1 bolt right in or will I have to do modification?

 

I've heard the 3.1 and 2.8 are the same blocks? I would assume that would mean the motor mounts are the same. But I'd get confirmation on that.

 

2.8, 3.1, 3.4 will bolt up in the same place. 3800 II will bolt up also if you make the brackets a certain way

 

 

Ok. Thanks alot for the replies. That helps me out alot!

 

Isn't the 3.8 a 90 degree?
If it is the tranny won't bolt up.

Sorry answered my own question from Wikipedia Encyclopedia...

"Another oddity of this engine is that although it is a 90° V6 it has the GM 60° V6 bell housing pattern when it is used in FWD or RWD applications (pre-3800 series RWD cylinder blocks incorporated the BOP bellhousing pattern). For use in the RWD applications, the bellhousings on both the manual and automatic transmissions are altered."

BOP is Buick Olds Pontiac for those of you who don't know...
it's amazing what happens when we

 

Yes but the question wasnt about the tranny, it was about the motor mounts. Nice try though

 

I understand that, but project 85 was reffering to a 2nd gen 3.8.
The 1st gen 3.8 will not bolt up to the tranny, hence my comment.
What good would it do if you could bolt it in the car if the tranny didn't line up?

 

it better bolt up!!!.....thats why i got the 3.4!!! lol